ISO/TR 21275:2017

TECHNICAL ISO/TR
REPORT 21275
First edition
2017-02
Rubber — Comprehensive review of
the composition and nature of process
fumes in the rubber industry
Caoutchouc — Examen exhaustif de la composition et de la nature des
fumées de process dans l’industrie du caoutchouc
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Overview of the rubber industry . 8
4.1 General . 8
4.2 Rubber component production processes . 8
4.3 Generic rubber types .11
4.4 Rubber chemicals and additives .12
4.5 Mechanistic chemistry of rubber vulcanization .13
4.5.1 Generality .13
4.5.2 Sulfur-accelerated cure systems.13
4.5.3 Peroxide-based cure systems .14
4.5.4 Metal oxides .14
4.5.5 Other vulcanizing systems.14
4.6 Effect of elevated temperature on rubbery polymers and rubber additives .15
5 Definition of rubber fumes .15
6 Nature and composition of rubber fumes .16
6.1 General .16
6.2 Key components of rubber fumes and their origin .16
6.3 Trapping and analysis of rubber fumes .17
6.3.1 General.17
6.3.2 Characterization studies carried out in factory environments .17
6.3.3 Characterization studies carried out under laboratory conditions .18
6.4 Changes in rubber technology that have influenced the nature and composition of
rubber fumes and improved the protection of workers in the industry .19
6.4.1 General.19
6.4.2 Overall trend in rubber workers’ exposure to total rubber fumes .19
6.4.3 Polyaromatic hydrocarbons .19
6.4.4 Nitrosamines .19
6.4.5 Silane coupling agents and resorcinol steel cord coating agent .19
7 Factors affecting the variability of rubber fumes .19
7.1 General .19
7.2 Influence of the rubber compound formulation on the composition of rubber fumes .20
7.3 Influence of different manufacturing processes on rubber fumes .20
7.4 Influence of different processing temperatures on the composition of rubber fumes .21
8 Review of literature on the composition and nature of rubber process fumes .22
8.1 Comprehensive literature search .22
8.1.1 General.22
8.1.2 Rubber fumes data obtained from factory atmospheres .22
8.1.3 Rubber fumes data obtained by laboratory studies .32
8.1.4 Research on sampling and analysis techniques for rubber fumes.36
8.1.5 Influence of rubber additives on the composition of rubber fumes .38
8.1.6 Work carried out at Rapra Technology Ltd. .40
8.2 Other sources of information .41
8.2.1 General.41
8.2.2 Search strategy for external databases .42
8.2.3 Chemical abstracts results .42
8.2.4 General POLLUAB and NTSI database results .43
8.2.5 Search of industry-relevant publications, government publications and
relevant websites . .43
9 Summary of the finding of the literature review .44
10 Conclusions .45
Annex A (informative) Abbreviated terms .47
Bibliography .49
iv © ISO 2017 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www . i so .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products.
Introduction
Fumes emitted during the rubber manufacturing processes were the topic of many studies. This
comprehensive study was undertaken to compile and review published data with respect to rubber
fume emissions in the workplace. This review has provided a comprehensive bank of technical data
for dissemination and further debate. It has assessed literature regarding the chemical composition
of rubber fumes in manufacturing from a comprehensive range of processes. It has been postulated
that fume emissions from rubber compound vulcanization can be considered a single chemical entity,
cited as posing a carcinogenic risk to human health. Although many studies have tried to characterize
rubber fume emissions, there is no known concise study that provides a rational explanation for this
conclusion. This study has tested this postulation and provided an insight as to whether it is a sound
conclusion.
The aim of this project was to evaluate, on a basis of sound scientific literature, whether it is
scientifically robust to consider “rubber fumes” as a homogeneous entity from a chemical point of view
and, more importantly, in relation to measurement and control of occupational exposure risk for the
rubber industry as a whole.
An extensive literature review aimed at providing a compilation of literature related to rubber fume
emissions, this study has concentrated on the chemical compositional aspects of rubber fumes only and
not on the toxicological or epidemiological aspects.
In addition, although rubber dust and rubber fumes are being considered by the EU for a potential
incorporation in the scope of the Carcinogens Directive, this study has only considered rubber fumes.
This document provides detailed information on the study carried out, the results obtained from the
literature reviews and the conclusions drawn from this information.
This document comprises two main parts; the first provides a general overview of the key areas of
rubber technology and the second provides an extensive review of in-house and external literature on
the composition and nature of rubber process fumes.
Natural rubber (NR) has been known to the civilized world since about 1493 when early European
explorers found natives of Haiti playing with balls made from the exudates of a tree called “cau-uchu”.
The term “rubber” was co
...